When compiling code such as the following:

with a
  with .b
    print .c

The correct output should be roughly equivalent to print a.b.c. However, this is not the case, and moonc bombs with an error when code like this is run, even in the presence of a suitable table structure (so that a.b.c is defined).
This is because moonc currently compiles the above snippet into this (note the _with_1.b part):

do
  local _with_0 = a
  do 
    local _with_1 = _with_1.b
    print _with_1.c
  end
end

This happens because when the transformer emits the _with_1 assignment, scope_var (which is used by values to look up the current scope when the short-dot syntax is used) has already been set to the new one (from the nested block). This fix simply reorders the scope_var assignment so that it happens after these statements have been emitted, so the correct scope is being used.
This PR fixes #187 (and #197, its dupe).